Eighteen workers were sicked by fumes after a chemical spill at a plant in southwest suburban Elwood this morning, officials said.

Two were taken to hospitals while 16 declined to go to a hospital.

At about 9:30 am there was a release of a heat transfer fluid at Stepan Company’s Millsdale plant, which led to a response by local fire departments and some emergency service personnel, Stepan spokeswoman Kim Kumiega said in an emailed statement.

Stepan Chemical is located at 22500 W. Millsdale Rd., according to the company website.The release occurred during start-up activity after planned maintenance was completed, Kumiega said. She described it as a "small release."

Workers were lifting a unit inside of a building when the unit “over pressurized’’ and released the chemical, Therminol, a heat-transfer fluid, said Will County sheriff’s spokeswoman Kathy Hoffmeyer.

Eighteen people were exposed to the vapor, said Hoffmeyer. Two were taken to hospitals and 16 signed refusals, Hoffmeyer confirmed.

“At no time were there any fires or explosions,’’ said Hoffmeyer, adding that the sheriff’s department was called to the scene to assist with traffic control.

As a precautionary measure, the 18, who are contract workers, were evaluated, said Kumiega. Sixteen of those contractors refused treatment and two were taken to the hospital for further evaluation.

No employees were affected and there is no impact to the community, Kumiega said in the email.